Possible mutual excitatory couplings between inspiratory neurons in caudal ventrolateral medulla of brainstem-spinal cord preparation isolated from newborn rat.

In in vitro brainstem-spinal cord preparations, projection of inspiratory neurons in the caudal ventrolateral medulla (CVL) was examined electrophysiologically, and connectivity between bilateral inspiratory neurons in the CVL was analyzed by pulse-cross correlation (PCC) analysis. CVL inspiratory neurons were found to project to the contralateral CVL and/or mainly ipsilateral spinal cord. PCC analysis revealed significant peaks with different latency on both sides of time zero in 3 of 8 pairs. Results were consistent with mono- or oligo-synaptic excitatory connections between bilateral inspiratory neurons in the CVL.